Shatter-resistant, optically-transparent panels and methods of use of the panels for on-site retrofitting and reinforcing of passageways

ABSTRACT

The disclosure includes multi-layered panels ( 10, 60, 204 ) including exterior layers of glass ( 12, 44 ) and interior layers of urethane ( 20, 36 ) and at least one layer of polycarbonate ( 16 ) between the urethane layers ( 20, 36 ) that result in enhanced shatter resistance within panels ( 10, 60, 204 ) that weigh between about 4.1 and 4.6 pounds per square foot. The panels ( 10, 60, 204 ) include an insertion tab ( 23, 61, 23 ″) of the polycarbonate layer ( 16 ) that enhances performance of the panel ( 10 ). Reinforced passageways ( 70, 200, 300 ) such as doors and windows of schools, hospitals and other public and private buildings, are disclosed using the multi-layered panel ( 10, 60, 204 ) with the insertion tab ( 23, 61, 23 ″).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part U.S. patent application Ser.No. 14/710,048 entitled “Shatter-Resistant, Optically-Transparent Panelsand Methods of Use of the Panels for On-Site Retrofitting andReinforcing of Passageways” that was filed on May 12, 2015, and is nowU.S. Pat. No. 9,365,015 that issued on Jun. 14, 2016, and thatapplication Ser. No. 14/710,048 claims the benefit of U.S. ProvisionalPatent Application Ser. No. 61/992,065 that was filed on May 12, 2014entitled “Shatter-Resistant, Optically-Transparent Panels and Methods ofUse of the Panels for On-Site Retrofitting and Reinforcing ofPassageways”.

TECHNICAL FIELD

This disclosure relates to shatter-resistant, optically-transparentpanels for use in glass passageways, such as doors or windows, toenhance security of the doors and/or windows. The disclosure alsorelates to a method of on-site retrofitting of the shatter-resistant,optically-transparent panels into existing door frames whilesimultaneously reinforcing the door frames.

BACKGROUND ART

It is well known that doorways to public buildings, such as schools,courthouses, etc., present security challenges in preventing unwantedpersons from entering through the doors. In a tragic example of asecurity failure of a common school door, on Dec. 14, 2012, an armedintruder shattered a front door of the Sandy Hook Elementary School inNewtown, Conn., U.S.A. and proceeded to shoot and kill 26 unarmedcivilians. The front door of the Sandy Hook Elementary School was onlytempered glass that shattered and collapsed upon impact with one bulletfired by the intruder from a gun so that the intruder could then walkthrough the door into the school.

Many efforts have been made to improve intrusion resistance of glassdoors of public and private buildings. For buildings housing high-valuepersons and or museum-type goods, it is well known to use thick,bullet-proof types of layered glass. For example, U.S. Pat. No.7,641,965 that issued on Jan. 5, 2010 to Bennison et al. and that isowned by E. I. du Pond de Nemours and Company, shows a multi-layeredoptically-transparent, ballistic resistant “safety glazing” or window.The Bennison et al. “safety glazing” has an impact zone at one surface,such as an exterior surface of a window of an armored vehicle, and ananti-spall surface to prevent fragments of the window from breaking offand impacting persons within the armored vehicle. In one embodiment,Bennison et al., shows windows having between five and eleven layers.While effective, such a complex window is both prohibitively expensiveand too heavy to be utilized in common doorways of public buildings,such as public schools, courthouses, university buildings, hospitals,etc.

More recently, U.S. Pat. No. 7,857,605 that issued on Jan. 11, 2011 toMoran et al. shows an intrusion resistant glass laminate for use betweentwo layers of glass to provide enhanced stiffness without loss ofoptical clarity. Moran et al. discloses stiffness factors that result inresistance to increasing numbers of axe-head impacts, 19.5 Kg. pendulumimpacts, blunt head impacts (for car windshields) and other intrusionrisks. Again, while thick, stiff safety glazed, transparent panelsprovide protection, they generally weigh in excess of 20 pounds persquare feet, and hence cannot be efficiently utilized in existingdoorways of public buildings.

Consequently, there is a need for a light-weight, shatter-resistant,transparent panel that can be efficiently retrofitted into existingdoorways at a minimum cost while providing substantially enhancedresistance to shattering to thereby provide a secure doorway.

SUMMARY OF THE DISCLOSURE

The disclosure is a shatter-resistant, optically-transparent panel forresisting breaking of the panel into pieces. The disclosure includes twoembodiments of the panel; a first thin embodiment, and a second thickembodiment. The disclosure also includes a method of using either thethin or thick embodiment to perform an on-site retrofitting andreinforcing of a traditional passageway such as a door or a windowsecured within a building, such as a school, hospital, etc.

The thin embodiment includes a first layer; being a glass sheet havingan exterior surface and an opposed interior surface, the first glasssheet having a thickness of about 3.048 millimeters [0.12″]; a secondlayer being a first urethane sheet having an upper surface securedadjacent the interior surface of the first glass sheet and having alower surface, the first urethane sheet having a thickness of about0.635 millimeters [0.025]; a third layer being a polycarbonate sheethaving an upper surface secured adjacent the lower surface of the firsturethane sheet and having a lower surface, the polycarbonate sheethaving a thickness of about 2.997 millimeters [0.118″]; a fourth layerbeing a second urethane sheet having an upper surface secured adjacentthe lower surface of the polycarbonate sheet and having a lower surface,the second urethane sheet having a thickness of about 0.635 millimeters[0.025]; and, a fifth layer being a second glass sheet having aninterior surface secured adjacent the lower surface of the secondurethane sheet and having an exterior surface, the second glass sheethaving a thickness of about 3.048 millimeters [0.120″]. The totalthickness of the thin embodiment is about 10.363 millimeters (“mm”)[0.408″].

The thick embodiment is similar to the thin embodiment but has seventotal layers having an additional urethane coated polycarbonate sheet.The seven layers include a first layer being a first glass sheet havingan exterior surface and an opposed interior surface, the first glasssheet having a thickness of about 3.048 millimeters [0.12″]; a secondlayer being a first urethane sheet having an upper surface securedadjacent the interior surface of the first glass sheet and having lowersurface, the first urethane sheet having a thickness of about 1.270millimeters [0.050″]a third layer being a first polycarbonate sheethaving an upper surface secured adjacent the lower surface of the firsturethane sheet and having a lower surface, the first polycarbonate sheethaving a thickness of about 2.997 millimeters [0.118″]; a fourth layerbeing a second urethane sheet having an upper surface secured adjacentthe lower surface of the first polycarbonate sheet and having a lowersurface, the second urethane sheet having a thickness of about 0.381millimeters [0.015″]; a fifth, layer being a second polycarbonate sheethaving an upper surface secured adjacent the lower surface of the secondurethane sheet and having a lower surface, the second polycarbonatesheet having a thickness of about 0.762 millimeters [0.030″]; sixthlayer being a third urethane sheet having an upper surface securedadjacent the lower surface of the second polycarbonate sheet and havinga lower surface, the third urethane sheet having a thickness of about1.270 millimeters [0.050″]; and, a seventh layer being a second glasssheet having an interior surface secured adjacent the lower surface ofthe third urethane sheet and having an exterior surface, the secondglass sheet and having a thickness of about 3.048 millimeters [0.120″].The total thickness of the thick embodiment is about 11.760 millimeters[0.463″].

For purposes herein, the word “about” is to mean plus or minustwenty-percent. Additionally, the opposed surfaces or the describedobject.

Both the thin and thick embodiments of the panel may be configured soeach of the five or seven layers are disposed to overlie adjacent layersand each of the five or seven layers are configured to be co-extensivewith each other so that each layer has a perimeter edge overlying aperimeter edge of an adjacent layer.

Additionally, both the thin and thick embodiments of the panels mayinclude the polycarbonate sheet of the thin embodiment, or the first andthickest polycarbonate sheet of the thick embodiment, overlying adjacentsheets and having at least a portion or all of perimeter edges of thepolycarbonate sheets define an insertion tab extending beyond theperimeter edges of the other sheets of the panels.

The disclosure includes a method of on-site retrofitting an reinforcinga passageway with a shatter-resistant, optically-transparent panel. Themethod includes removing exterior stops surrounding an exterior surfaceof the passageway between a passageway frame and glass to be replaced;then, removing the glass to be replaced. Weather stripping is then takenoff of the removed exterior stops and from the interior stops thatremain surrounding the passageway frame. To reinforce the existingpassageway frame and the exterior and interior stops, the interior stopsare first drilled and metal screws counter sunk into the interior stopsand the metal screws pass through the interior stops and into thepassageway frame at least 13 mm [about 0.5 inches] and every 304 mm [12inches] on-center starting at a center of each stop. A minimum of threescrews are required for each stop unless the stop is less than 304 mm[12 inches] in length. The metal screws are flat headed screws, and arenot smaller than a size 8 screw. (For purpose herein, “size 8 screw” isto mean that a diameter of the threaded shaft of the screw is about4.1656 mm [0.1640 inches].) After the interior stops are therebyreinforced, the exterior stops are reinserted into the passageway frame,and then reinforced in the same manner as the interior stops asdescribed above. The reinforcing screws the exterior stops arepositioned so that the screws in the exterior stops are aligned with thescrews in the interior stops.

After reinforcing the stops, the exterior stops are removed, and then a3.048 mm [0.120 (⅛) inch] bead of a blast proof caulking is applied at abase of the interior stop and the passageway frame surrounding an entireperimeter of the passageway frame. The blast proof caulking may becaulking known as “Dow Corning 995 Structural Glazing Bomb BlastSilicone Sealant” that is commonly available. Then, the method includesinstalling either the thin or thick embodiment of the shatter-resistant,optically-transparent panel into the passageway frame adjacent the beadof caulking.

Next, a 3.048 mm [0.120 (⅛) inch] bead of the blast proof caulking isapplied along an entire exterior perimeter of the selected panel wherethe panel meets the passageway frame. The exterior stops are theninstalled so that holes drilled in the stops align with holes drilled inthe passageway frame. Finally, a bead that is than 3.048 mm [0.120 (⅛)inch] of the blast proof caulking is applied within a gap between theexterior surface of the selected panel and the exterior stops, and isalso applied within a gap between the interior surface of the selectedpanel and the interior stops.

An additional embodiment includes a first reinforced passageway, such asa door or a window, etc. The first reinforced passageway includes thepassageway having a frame surrounding a transparent panel. The frameincludes a first structural surface, an opposed second structuralsurface and a top structural surface secured perpendicular to andextending between top edges of the first and second structural surfaces.

More specifically, the first reinforced passageway includes an integralfirst stop and base plate wherein the base plate is secured adjacent toand parallel with the top structural surface. An outside wall of thefirst stop is secured to the base plate and adjacent the top edge of thefirst structural surface. The outside wall extends in parallelassociation with and away from the first structural surface. An insidewall of the first stop is secured to the base plate and is opposed tothe outside wall. The inside wall extends in parallel association withthe outside wall away from the base plate and top structural surface.The base plate also includes a plate extension that extends along thetop structural surface in a direction away from the outside and insidewalls of the first stop. A first fastener passes through the base plateextension to fasten the integral first stop and base plate to the topstructural surface.

A bead of blast proof caulking is secured over the first fastenerbetween and along the base plate extension and along a lower portion ofthe inside wall of the first stop. A first layer of glazing tape issecured to an upper portion of the inside wall. The glazing tape extendsfrom adjacent the bead of blast proof caulking along the inside wallparallel to the bead, and the glazing tape also extends to cover theupper portion of the inside wall. A setting block is secured within thebead of blast proof caulking and adjacent the base plate extension.

The optically-transparent panel is secured within the bead of blastproof caulking upon the setting block, and is also secured adjacent thelayer of glazing tape. The optically-transparent panel may be either theabove described thin embodiment or the thick embodiment of thetransparent panel. For purpose of efficiency, the aforesaid thin andthick embodiments of the transparent panel are also described as ashatter-resistant five-layer thin panel or a shatter-resistantseven-layer thick panel, wherein each of the panels includes opposedfirst and second glass sheets, first and second urethane sheets betweenthe first and second glass sheets, and a polycarbonate sheet between theurethane sheets. The transparent panel has a weight no greater thanabout 4.6 pounds per square foot, and the polycarbonate sheet defines aninsertion tab extending beyond a common perimeter edge defined by theglass sheets and the urethane sheets overlying each other. Theoptically-transparent panel is cured to the integral first stop and baseplate so that the insertion tab is adjacent the setting block.

The first embodiment of the reinforced passageway also includes a secondstop having an outside wall of the second stop that is secured to thetop structural surface and is also secured adjacent the top edge of thesecond structural surface. The outside wall of the second stop extendsin parallel association with and away from the second structuralsurface. The second stop also includes an inside wall of the second stopthat is also secured to the top structural surface and is opposed to theoutside wall. The inside wall extends in parallel association with theoutside wall away from the top structural surface. A second fastenerpasses through a top surface of the second stop between the inside andoutside walls of the second stop and through the top structural surfaceof the frame to secure the second stop to the top structural surface ofthe frame. A second layer of glazing tape is secured to an upper portionof the inside wall of second stop. The second layer of glazing tapeextends along the inside wall of the second stop adjacent thetransparent panel, and the tape extends along the inside wall of thesecond stop to cover the upper portion of the inside wall of the secondstop. The first and second layers of glazing tape cooperate to preventthe optically-transparent layer from contacting metal material formingthe first and second stops.

In an additional aspect of the first reinforced passageway, theinsertion tab extends away from the common perimeter edge a distance ofabout one-sixteenth of an inch.

In another aspect of the first reinforced passageaway, theshatter-resistant, optically-transparent panel is configured so that anentire perimeter edge of the polycarbonate sheet defines the insertiontab so that the insertion tab of the polycarbonate sheet extends beyondthe entire common perimeter edge.

In a further aspect of the first reinforced passageway, the outside wallof the second stop and the second structural surface form part of aninterior side of the reinforced passageway. By “interior side” it ismeant that the passageway is part of an enclosed structure, having and“inside volume” enclosed by walls, a roof and passageways, etc. The“interior side” is a surface of the reinforced passageway facing theinside volume of the enclosed structure. Keeping the second fastener ofthe second stop in the interior of the enclosed structure prevents anunwanted intruder from unfastening the second stop to mechanicallyremove the shatter-proof, optically-transparent panel.

Yet another embodiment is a second reinforced passageway, such as a dooror a window, etc., that substantially improves two-piece kits known inthe art to secure transparent panels to frames. The second reinforcedpassageway includes a frame surrounding the transparent panel. The frameincludes a first structural surface, an opposed second structuralsurface and a top structural surface secured perpendicular to andextending between top edges of the first and second structural surfaces.

More particularly, the second reinforced passageway includes, a firstpiece of a two-piece transparent panel mounting kit. The first piece hasa first wall secured adjacent the top edge of the first structuralsurface, and the first wall extends a pre-determined distance away fromthe first structural surface and the top structural surface. The firstwall also includes a first cavity wall extending back toward the topstructural surface. The first wall also includes a first grab-cleat thatextends below the top edge of the first structural surface and issecured adjacent the first structural surface. The second embodiment ofthe reinforced passageway also includes a second piece of the two-piecetransparent panel mounting kit. The second piece has a second wallsecured adjacent the top edge of the second structural surface and thesecond wall extends a pre-determined distance away from the secondstructural surface and the top structural surface. The second wall alsoincludes a second cavity wall that extends toward the top structuralsurface. The second wall also includes a second grab-cleat that extendsbelow the top edge of the second structural surface and is securedadjacent the second structural surface. The first cavity wall and thesecond cavity wall are configured to define a panel mounting cavitybetween the cavity walls. A bead of blast proof caulking is securedwithin the mounting cavity between the cavity walls and adjacent lowerportions of the first and second cavity walls. A first layer of glazingtape is secured along an upper portion of the first cavity wall. Asecond layer of glazing tape is secured along an upper portion of thesecond cavity wall.

The optically-transparent panel is secured within the mounting cavity,within the bead of blast proof caulking in the mounting cavity, andbetween and adjacent the first and second layers of glazing tape on thefirst and second cavity walls. The optically-transparent panel is ashatter-resistant five-layer thin panel or a shatter-resistantseven-layer thick panel, as described above. Each of the panels includesopposed first and second glass sheets, first and second urethane sheetsbetween the first and second glass sheets, and a polycarbonate sheetbetween the urethane sheets. The transparent panel has a weight nogreater than about 4.6 pounds per square foot. Additionally, thepolycarbonate sheet defines an insertion tab extending beyond a commonperimeter edge defined by the glass sheets and the urethane sheetsoverlying each other. The optically-transparent panel is secured withinthe mounting cavity so that the insertion tab is closer to the topstructural surface than the common perimeter edge. A kit-fastener passesthrough the first and second piece of the two-piece transparent panelmounting kit, and the kit-fastener and two pieces of the kit areconfigured so that the kit-fastener selectively draws the two piecestoward each other to thereby decrease a volume within the mountingcavity to secure the optically-transparent panel within the mountingcavity of the two-piece kit.

In another aspect of the second reinforced passageway, the insertion tabextends away from the common perimeter edge a distance of aboutone-sixteenth of an inch.

In an additional aspect of the second reinforced passageway, an entireperimeter edge of the polycarbonate sheet defines the insertion tab sothat the insertion tab of the polycarbonate sheet extends beyond theentire common perimeter edge.

In a further aspect of the second reinforced passageway, thekit-fastener comprises a metal screw having a driving head and threadedbody wherein the driving head is secured adjacent one of the first andsecond pieces of the two-piece kit. The piece with the driving head ofthe metal screw forms part of an interior side of the reinforcedpassageway.

Testing by the inventors has established an enormous increase inshatter-resistance of the described panels that provides dramaticallyenhanced security for persons within an interior of a building protectedby the passageways, such as doors and windows, retrofitted with the thinor thick embodiments of the present disclosure. Prior efforts to obtainanywhere near the same level intrusion resistance necessarily includedcomplete removal of the passageway frame and replacement with a framethat can support bullet-proof or intrusion resistant glass weighingtypically more than 25 pounds per square foot, which is a very costlyand time-consuming undertaking. In contrast, the panels of the presentthin and thick embodiments weigh between about 4.1 pounds and 4.6 poundsper square foot, and hence can be easily supported by standard doorpassageway frames and hardware configured to support standard glasspanels commonly utilized in public school buildings.

Again, the present invention, especially the embodiments of the thin andthick panels that include the extending polycarbonate layers having theextending insertion tabs, have been successfully tested to withstandextraordinary intrusion efforts. In one test, more than five bulletsfrom a Hungarian made “AK-47” rifle firing 7.62 mm rounds defined asemi-circle of penetration through a thick embodiment of the panelwithin a standard school door frame. The semi-circle of holes was arounda lock access and positioned in an effort to permit the shooter to knockout or shatter a section of the panel around a hand actuated interiorlock of the door. The panel did not fail. Then, a two-hundred poundsplus male swung a baseball bat at the semi-circle as hard as he couldfor over fifty strikes. The panel did not fail. Instead, the door framefailed, leading the inventors herein to develop the above-describedpassageway frame reinforcing system integrated with the on-siteretrofitting system.

The inventors have concluded that their present disclosure presentsextraordinary benefits in efficiently and quickly enhancing the securityof public schools especially, and other public and private buildings. Inlight of the tragedy of the Newtown Conn. massacre described above, thepresent disclosure provides an immeasurable value for the security ofchildren and others faced with the terror of unrestrained violence.

Accordingly, it is a primary purpose of the present disclosure toprovide a shatter-proof optically resistant panel for resisting breakingof the panel into pieces and an efficient, inexpensive method of usingthe panels for on-site retrofitting and reinforcing of passageways withthe panels. These and other advantages purposes of the presentdisclosure will become apparent when the following description is readalong with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is cross-sectional, fragmentary, schematic view of a thinembodiment of a shatter-resistant, optically-transparent panelconstructed in accordance with the present disclosure.

FIG. 2 is a cross-sectional fragmentary, schematic view of a thickembodiment of a shatter-resistant, optically-transparent panelconstructed in accordance with the present disclosure.

FIG. 3 is simplified front plan view of a door passageway within which ashatter-resistant, optically-transparent panel constructed in accordancewith the present disclosure may be secured.

FIG. 4 is a fragmentary, cross-sectional view of a portion of the FIG. 3door passageway taken along view line 4-4 of FIG. 3, and showing a frameof the door passageway reinforced by insertion of a shatter-resistant,optically-transparent panel constructed in accordance with the presentdisclosure.

FIG. 5 is a fragmentary, cross-sectional view of a frame of a firstreinforced passageway showing an integral first stop and base plate,showing a first fastener passing through a base plate extension, andshowing a second fastener passing through a second stop.

FIG. 6 is a fragmentary, cross-sectional view of the FIG. 5 frame,showing a bead of blast proof caulking between the base plate extensionand an inside wall of the first stop, showing a first strip of glazingtape adjacent the bead of caulking and an upper portion of the insidewall, and showing a shatter-proof, optically-transparent panel seatedupon a setting block within the bead of caulking.

FIG. 7 is a fragmentary, cross-sectional view of the FIG. 6 frame,showing a second stop secured by a second fastener to a top structuralsurface of the frame, showing a second strip of glazing tape along anupper portion of an inside wall of the second stop, and showing thesecond strip of glazing tape adjacent the optically-transparent panel.

FIG. 8A is a fragmentary, cross-sectional view of a second reinforcedpassageway embodiment of the present disclosure, showing a first pieceof a two-piece kit secured by a kit-fastener to a second piece of thetwo-piece kit upon a top structural surface of the frame and showing ashatter-resistant, optically-transparent panel secured within a mountingcavity between the two-pieces.

FIG. 8B is an expanded view of a circled portion of FIG. 8A showing theoptically-transparent passel within the mounting cavity with aninsertion tab of the panel positioned closest to the top structuralsurface of the frame of the second reinforced passageway.

PREFERRED EMBODIMENTS OF THE DISCLOSURE

Referring to the drawings in detail, a thin panel embodiment of ashatter-resistant, optically-transparent panel is shown in across-sectional, fragmentary and simplified view in FIG. 1 and isgenerally designated by the reference numeral 10. The thin panelembodiment 10 includes first layer 12 that includes a first glass sheet14 having an exterior surface 16 and an opposed interior surface 18. Thefirst glass sheet 14 has a thickness of about 3.048 millimeters [0.12″].The thin embodiment 10 also includes second layer 20 made of a firsturethane sheet 22 that has an upper surface 24 that secured adjacent theinterior surface 18 of tine first glass sheet 14. The first urethanesheet 22 also has a lower surface 26 opposed to the upper surface 24.The first urethane sheet 22 has thickness of about 0.635 millimeters[0.025]. A third layer 28 is made of a polycarbonate sheet 30 that hasan upper surface 32 secured adjacent the lower surface 26 of the firsturethane sheet 22. The polycarbonate sheet 30 also has a lower surface34, and the polycarbonate sheet 30 has a thickness of about 2.997millimeters [0.118″].

The thin panel embodiment 10 also has a fourth layer 36 made of a secondurethane sheet 38 having an upper surface 40 secured adjacent the lowersurface 34 of the polycarbonate sheet 30, and also having a lowersurface 42. The second urethane sheet 38 has a thickness of about 0.635millimeters [0.025″]. The thin embodiment 10 also has a fifth outerlayer 44 made of a second glass sheet 46 which has an interior surface48 secured adjacent the lower surface 42 of the second urethane sheet38. The second glass sheet 46 also has an exterior surface 50, and thethickness of the second glass sheet 46 is about 3.046 millimeters[0.120″].

As recited above, for purposes herein, the word “about” is to mean plusor minus twenty-percent. Additionally, the word “thickness” is to mean ashortest distance between opposed surfaces or the described object.

It is to be understood that the word “urethane” as used herein toidentify the two urethane sheets 22, 38 includes “polyurethane” andother polymers composed of a chain of organic units joined by carbamate(urethane) links. The purpose of the urethane layers 22, 38 in thepresent invention is to facilitate bonding of the extremely hardpolycarbonate sheet 30 to the exterior glass layers 14, 46, and toprovide elasticity that prevents cracking of any of the hard layers ofthe thin panel 10 when exposed to thermal stresses. Any other compoundknown to achieve that goal and that is known in the intrusion-resistant,bullet-proof panel arts may be used with or instead of the urethanelayers and be within the scope of the present disclosure. Similarly, theword “polycarbonate” is to mean any polymer containing carbonate groups(—O—(C═O)—O—). An exemplary polycarbonate is sold under the trademark“LEXAN” and is commonly available from a SABIC Innovative Plasticscompany (formerly General Electric Plastics), of Pittsfield, Mass.,United States of America.

FIG. 2 shows a schematic, fragmentary embodiment of a thick panelembodiment 60 of the present shatter-proof, optically-transparent paneland is generally designated by the reference numeral 60. The thick panelembodiment 60 includes five layers that are very similar to the fivelayers of the above-described thin panel embodiment, and also includestwo additional layers. For purposes of efficiency and ease ofexplanation, the layers of the thick panel embodiment 60 that are verysimilar to the layers described above for the thin panel embodiment 10will be associated with primes of the reference numerals for the FIG. 1,thin panel embodiment 10. For example, the first layer of the thin panelembodiment 10 is associated with the reference numeral 12, and the firstlayer of the thick panel embodiment 60 will be associated with thereference numeral 12′.

The thick embodiment 60 include a first layer 12′ made of a first glasssheet 14′, and it has an exterior surface 16′ and an opposed interiorsurface 18′. The first glass sheet 14′ has a thickness of about 3.048millimeters [0.12″]. The thick panel embodiment 60 also includes secondlayer 20′ made of a first urethane sheet 22′ that has an upper surface24′ secured adjacent the interior surface 18′ of the first glass sheet14′. The first urethane sheet 22′ also has a lower surface 26′, and thefirst urethane sheet 22′ of the thick panel embodiment has a thicknessof about 1.270 millimeters [0.050″]. The thick panel embodiment 60 alsoincludes a third layer 28′ made of a first polycarbonate sheet 30′ thathas an upper surface 32′ secured adjacent the lower surface 26′ of thefirst urethane sheet 22′ and has a lower surface 34′. The firstpolycarbonate sheet 30′ of the thick panel 60 has a thickness of about2.997 millimeters [0.118″]. A fourth layer 36′ is made of a secondurethane sheet 38′, and it has an upper surface 40′ that is securedadjacent the lower surface 34′ of the first polycarbonate sheet 30′, andit also a lower surface 42′. The second urethane sheet 38′ of the thickpanel 60 has a thickness of about 0.381 millimeters [0.015″].

The thick panel embodiment 60 includes a different fifth layer than thethin panel embodiment 10, and hence will not be represented by primereference numerals and will be referred to as a fifth non-outer layer62. The fifth non-outer layer is made of a second polycarbonate sheet 64having an upper surface 66 secured adjacent the lower surface 42′ of thesecond urethane sheet 38′ and having a lower surface 68. The secondpolycarbonate sheet 64 has a thickness of about 0.762 millimeters[0.030″]. The thick panel 60 also has a sixth layer 63 that is made of athird urethane sheet 65 having an upper surface 67 secured adjacent thelower surface 68 of the second polycarbonate sheet 64. The thirdurethane sheet 65 also has a lower surface 69, and the third urethanesheet has a thickness of about 1.270 millimeters [0.050″]. The thickpanel embodiment 60 also has an outer seventh layer which very similarto the fifth outer layer 44 of the thin embodiment 10. Therefore,components of the seventh outer layer of the thick embodiment 60 will beassociated prime reference numerals of the fifth outer layer 44 of thethin embodiment 10. The seventh outer layer 44′ is made of a secondglass sheet 46′ having an interior surface 48′ secured adjacent thelower surface 69 of the third urethane sheet 65 and having an exteriorsurface 50′, the second glass sheet having a thickness of about 3.048millimeters [0.120″].

FIG. 1 also shows that the thin panel embodiment 10 defines a commonperimeter edge 11 which is a farthest planer extension of all of thefive layers 12, 20, 28, 36, 44 making up the thin panel embodiment 10.The five layers making up the thin panel 10 all share the commonperimeter edge 11 so that all five layers overlie each other to definethe common perimeter edge 11. However, a portion of the third layer 28made of the first polycarbonate sheet 30 may define an insertion tab 23that extends beyond the common perimeter edge 11. The insertion tab 23may be one tab 23 that extends coextensively with the entire perimeteredge 11 of the panel 10, or the insertion tab 23 may be one of manyinsertion tabs 23 defined at predetermined locations along the perimeteredge 11 to help secure the panel 10 within a place of use of the panel10, such as shown in FIG. 3.

Similarly, the FIG. 2 shows that the thick panel embodiment 60 defines aperimeter edge 59 which is a farthest planer extension of all of theseven layers 12′, 20′, 28′, 36′, 62, 63, 44′ making up the thick panelembodiment 60. The seven layers making up the thick panel embodiment 60all share the common perimeter edge 59 so that all seven layers overlieeach other to define the common perimeter edge 59. However, a portion ofthe third layer 28′ made of the first polycarbonate sheet 30′ may definea second insertion tab 61 that extends beyond the common perimeter edge59. The second insertion tab 61 may be one tab 61 that extendscoextensively with the entire perimeter edge 59 of the panel 60, or thesecond insertion tab 61 may be one of many second insertion tabs 61defined at predetermined locations along the perimeter edge 59 to helpsecure the panel 60 within a place of use of the panel 60 (shown insubsequent FIGS.).

FIG. 3 is a simplified front plan view of a door passageway 70. Thepassageway includes a surrounding frame 72 for securing and supporting ashatter-resistant, optically-transparent panel 73 constructed inaccordance with the present disclosure. The door passageaway 70 may alsoinclude standard hinges 74A, 74B for hinging the door 70 into a buildingopening (not shown), and a standard door latch 76 for opening the door70. Additionally, FIG. 3 shows the door passageway upon a standard sill78 below the door 70.

FIG. 4 is a fragmentary, cross-sectional view of a portion of the FIG. 3door passageway 70 taken along view line 4-4 of FIG. 3. FIG. 4 shows alower section 80 of the door passageway 70 of FIG. 3. The lower section80 is positioned above the sill 78 within a passageway over which aperson would walk to pass through the passageway 70. The lower section80 includes an interior structural surface 84 and an opposed exteriorstructural surface 86 having ordinary metal door structural supportcomponents 88 between the structural surfaces 84, 86. An interior stop90 is shown secured within a door-frame compression receiver 92. Thedoor-frame compression receiver 92 includes an interior grab-clip 93,and an opposed exterior grab-clip 95 at opposed outer edges of a topsurface 98 of the compression receiver 92. The top surface 98 servesboth a base 98 of the compression receiver 92 as well as a topstructural surface 98 of the lower section 80 of the frame 72 of thedoor. An exterior stop 94 is shown at the opposed exterior surface 86,and is secured against the exterior grab-clip 95 of the compressionreceiver 92.

The interior stop 90 is shown having a reinforcing “No. 8 Metal Screw”96 pack through the stop 90 and passing through the top surface 98 ofthe door-frame compression receiver 92, wherein the top surface 98extends between top edges of the interior surface 84 and the exteriorsurface 86. The phrase “No. 8 Metal Screw” is an exemplary fastener.However, any metal screw or fastener is acceptable if it is about atleast as wide as a No. 8 screw and that will pass completely through theinterior and exterior stops 90, 94 and through the top surface 98 of thedoor-frame compression receiver 92 a distance about as long as 25% of avertical length of the interior and exterior stops 90, 94 and that isalso parallel to the interior and exterior surfaces 84, 86. FIG. 4 showsthat the exterior stop 94 also has a second reinforcing metal screw 100passing through the stop interior 90 and into and through the topsurface 98 of the door-frame compression receiver 92.

FIG. 4 also shows a section of a thin panel embodiment 102 of thepresent shatter-proof, optically-transparent panel 102 which isconstructed as described above for the FIG. 1 thin panel embodiment 10.The FIG. 4 thin panel embodiment 102 is secured between the interiorstop 90 and the exterior stop 94, and with a beads 104A, 104B of blastproof caulking secured between opposed sides of the panel 102 and theinterior stop 90 and exterior stop 94. (As described above, the blastproof caulking may be caulking known as “Dow Corning 995 StructuralGlazing Bomb Blast Silicone Sealant” that is commonly available. FIG. 4also shows an insertion tab 106 of a polycarbonate layer (shown in FIG.1 at ref. no. 30) extending below a perimeter edge 108 the panel 102 tocontact the upper surface 98 of the door-frame compression receiver 92.Because the insertion tab 106 extends below the perimeter edge 108 ofthe panel 102, an interior pivot void 110 and an exterior pivot void 112are defined on opposed sides of the insertion tab 106, between the uppersurface 98 of the door-frame compression receiver 92 and the perimeteredge 108 of the panel 102. The pivot voids 110, 112 substantiallyenhance the resistance of the panel 102 to shattering upon an impactagainst either of the opposed exterior surfaces (shown in FIG. 1 at ref.nos. 16 and 50) because the insertion tab 106 may pivot into the pivotvoids 110, 112 instead of being firmly clamped, with no room formovement in response to the impact. Repeated experiments demonstratedthat the panel 102 exhibits much greater, shatter resistance through useof the insertion tab 106 compared to a panel (not shown) without theinsertion tab 106, and this is most likely due to the pivot voids 110,112. Additionally, the insertion tab 106 greatly enhances a bond betweenthe panel 102, the interior and exterior stops 90, 94 and the uppersurface 98 of the door-frame compression receiver 92. This disclosureincludes a passageway 70 having the above described insertion tab 106 ofthe panel 10, 60 and the adjacent pivot voids 110, 112.

The present disclosure also includes a method of on-site retrofittingand reinforcing a passageway with a shatter-resistant,optically-transparent panel. By retro-fitting “on-site”, the method doesnot require removal of the passageway, such as the FIG. 3 doorpassageway 70, from the location wherein the door 70 is being used. Thisis an enormous cost-savings. Otherwise, a temporary door (not shown)would have to be replace the door 70 for off-site reinforcement.

The method includes the steps of first removing the exterior stops 94surrounding an exterior surface 86 of the door 70. The exterior 94 arelocated between the passageway 70 structural support frame 72 and glass(not shown) to be replaced. Then, the glass to be replaced is removed.Any weather stripping is then taken off of the removed exterior stopsand from the interior stops 90 that remain surrounding the passagewayframe 72. To reinforce the existing passageway frame 72 and the exteriorand interior stops 94, 90, the interior stops 90 are first drilled andthe above described interior metal screws 96 are counter sunk into theinterior stops 90 and the metal screws pass through the interior stops90 and into the top surface 98 of the passageway frame at least 13 mm[about 0.5 inches]. The interior screws 96 are positioned every 304 mm[12 inches] along the interior stop 90 on-center starting at a center ofeach interior stop 90. A minimum of three screws are required for eachstop 90 unless the stop is less than 304 mm [12 inches] in length.

The metal screws 96 are flat headed screws, and are not smaller than asize 8 screw. (For purposes “size 8 screw” is to mean that a diameter ofthe threaded shaft of the screw is about 4.1656 mm [0.1640 inches].)After the interior stops 90 are hereby reinforced, the removed exteriorstops 94 are reinserted into the frame 72 of the passageway 70, and thenreinforced in the same manner as the interior stops 96 as describedabove, through insertion of the exterior metal screws 100. Thereinforcing screws 100 of the exterior stops 94 are positioned so thatthe screws 100 in the exterior stops 94 are aligned with the screws 96in the interior stops 90.

After reinforcing the 90, 94, the exterior stops 94 are removed, andthen an interior bead 104A of about 3.048 mm [0.120 (⅛) inch] diameterof the blast proof caulking 104A is applied at a base of the interiorstops 90 and the top surface 98 of the door frame compression receiver92 so that the bead 104A surrounds an entire perimeter of the passagewayframe 72. Then, the method includes installing one of the thin panelembodiment 10 and the thick panel embodiment 60 of theshatter-resistant, optically-transparent panel 10, 60 into thepassageway frame 72 adjacent the bead 104A of caulking.

Next, another exterior 3.048 mm [0.120 (⅛) inch] bead 104B of the blastproof caulking is applied along an entire exterior perimeter of theselected panel 10, 60 where the panel 10, 60 meets the top surface 98 ofthe door frame compression receiver 92. The exterior stops 94 are theninstalled into the frame 72 so that holes drilled in the stops 94 alignwith holes drilled in the top surface 98 of the passageway frame 72.Finally, an interior supplemental bead 112 that is less than 3.048 mm[0.120 (⅛) inch] of the blast proof caulking is applied within any gapbetween the interior surface 50, 50′ of the selected pane 10, 60 and theinterior stops 90, and an exterior supplemental bead 114 may be appliedwithin any gap between the exterior surface 16, 16′ of the selectedpanel 10, 60 and the exterior stops 94. The door frame 72 is therebysubstantially reinforced at the site of its usage, while theshatter-resistant transparent panels 10, 60 have also enormouslyincreased the safety of the door 70. In many instances, the door 70 maybe reinforced in the above manner without even removing it from itshinges 74A, 74 b, to further reduce the cost of reinforcing the door 70while replacing non-shatter resistant transparent panels (not shown).

As best shown in FIG. 7, an additional embodiment of the presentdisclosure includes a first reinforced passageway that is shown in FIG.7 in a fragmentary, cross-sectional view and is generally designated bythe reference numeral 200. An entire first reinforced passageway (notshown) may be in the form of a door car a window, similar to thepassageway 72 shown in FIG. 3. The first reinforced passageway 200includes the passageway 200 having a frame 202 surrounding a transparentpanel 204. The frame 202 includes a first structural surface 206, anopposed second structural surface 208 and a top structural surface 210secured perpendicular to and extending between a top edge 212 of thefirst structural surface 206 and a top edge 214 of the second structuralsurface 208, as shown in FIGS 5-7. (The top structural surface 210 shownin FIGS. 5-7 includes empty stop sleeves 216A, 216B that have hadconventional stops (not shown) removed, wherein the first reinforcedpassageway 200 is being retrofitted to a frame 202 previously used withconventional stops (not shown).)

More specifically, the first reinforced passageway 200 includes anintegral first stop and base plate 218 that includes a box-like firststop 220 having a base plate 222 as a base of the first stop 220 andextending away from the first stop 220. The base plate 222 is securedadjacent to and parallel with the top structural surface 210. An outsidewall 224 of the first stop 220 is secured to the base plate 222 andadjacent the top edge 212 of the first structural surface 206. Theoutside wall 224 extends in parallel association with and away from thefirst structural surface 206. An inside wall 226 of the first stop 220is secured to the base plate 222 and is opposed to the outside wall 224.The inside wall 226 extends in parallel association with the outsidewall 224 away from the base plate 222 and top structural surface 210.The base plate 222 also includes a plate extension 228 that extendsalong the top structural surface 210 in a direction away from theoutside wall 224 and inside wall 226 of the first stop 220, as shown inFIGS. 5-7. A first fastener 230 passes through the base plate extension228 to fasten the integral first stop and base plate to the topstructural surface. It is noted that the base plate extension 228 isshown in FIGS. 5-7 as covering the entire top structural 210. However,the extension 228 need only extend away from the first stop 220 farenough to be able to have the first fastener 230 pass through theextension 228.

A bead of blast proof caulking 232 is secured over the first fastener230 between and along the base plate extension 228 and along a lowerportion 234 of the inside wall 226 of the first stop 220. A first layerof glazing tape 236 is secured to an upper portion 238 of the insidewall 226. The glazing tape 236 extends from adjacent the bead of blastproof caulking 232 along the inside wall 226 parallel to the bead 232,and the glazing tape 236 also extends to cover the upper portion 238 ofthe inside wall 226. A setting block 240 is secured within the bead ofblast proof caulking 232 and adjacent the base plate extension 228.

The first layer of glazing tape 236, and other layers of glazing tapeidentified below, include “glazing tape” known in the transparent glasspanel industry, such as a closed cell sealant made of closed cellpolyvinyl chloride foam tape having a pressure sensitive adhesive on oneor two exterior sides of the tape. Such a glazing tape is available fromthe Anemostat Door Products company of Carson, Calif. (seewww.anemostat.com/DoorProducts/literature/tape.pdf). Such glazing tapeshave a limited range of compression and are available in thicknessranging generally between about one thirty-second of an inch ( 1/32″)and about one-quarter of an inch (¼″). Additionally, the setting block240 may be any of a variety of “setting blocks” that are well-known inthe transparent glass panel industry, such as santoprene setting blocksthat are compatible with polycarbonate layers that are available fromReed Rubber Products, Inc. of Saint Louis, Mo. (Seewww.reedrubberproducts.com/glazing-neoprene-setting-blocks.html.)

The optically-transparent panel 204 is secured within the bead of blastproof caulking 232 upon the setting block 240, and is also securedadjacent the first layer of glazing tape 236. The optically-transparentpanel may be either the above described thin embodiment of thetransparent panel 10 (shown in FIG. 1) or the thick embodiment of thetransparent panel 60 (shown in FIG. 2). For purpose of efficiency, theaforesaid thin 10 and thick 60 embodiments of the transparent panel arealso described as shatter-resistant five-layer thin panel 10, 204 and ashatter-resistant seven-layer thick panel 60, wherein each of the panelincludes opposed first and second glass sheets 14, 46, 14″, 46″ (layersof the thin embodiment 10 shown in FIGS. 6 and 7 for the five-layer thinpanel 204 are show as double primes of the reference numerals shown inFIG. 1), first and second urethane sheets 22, 38, 22″, 38″ between thefirst and second glass sheets, and a polycarbonate sheet 30, 30″ betweenthe urethane sheets. The transparent panel 204 has a weight no greaterthan about 4.6 pounds per square foot, and the polycarbonate sheet 30″defines an insertion tab 23″ extending beyond a common perimeter edge11″ defined by the glass sheets and the urethane sheets overlying eachother. The optically-transparent transparent panel 204 is secured to theintegral first stop and base plate 218 so that the insertion tab 23″ isadjacent the setting block 240.

The first embodiment of the reinforced passageway 200 also includes asecond stop 242 having an outside wall 244 of the second stop 242 thatis secured to the top structural surface 210 and is also securedadjacent the top edge 214 of the second structural surface 208. Theoutside wall 244 of the second stop 242 extends in parallel associationwith and away from the second structural surface 208. The second stop242 also includes an inside wall 246 of the second stop 242 that is alsosecured to the top structural surface 210 and is opposed to the outsidewall 244. The inside wall 246 extends in parallel association with theoutside wall 244 away from the top structural surface 210. FIG. 5 showsthat the integral first stop and base plate 218 along with the secondstop 242 are applied to descend upon the top structural surface 210 fromabove the surface 210, as represented in FIG. 5 by directional arrows247. FIG. 6 and 7 show the integral first stop and base plate 218 alongwith the second stop 242 secured upon the top structural surface 210.

A second fastener 248 passes through a top surface 250 of the secondstop 242 between the inside and outside walls 246, 244 of the secondstop 242 and through the top structural surface 210 of the frame 202 tosecure the second stop 242 to the top structural surface 210 of theframe 202. A second layer of glazing tape 252 (shown only in FIG. 7) issecured to an upper portion 254 of the inside wall 246 of the secondstop 242. The second layer of glazing tape 252 extends along the insidewall 246 of the second stop 242 adjacent the transparent panel 204, andthe tape 252 extends along the inside wall 246 of the second stop 242 tocover the upper portion 254 of the inside wall 246 of the second stop242. The first layer 236 and second layer 252 of glazing tape cooperateto prevent the optically-transparent panel 204 from contacting metalmaterial forming the first and second stops 220, 242.

In an additional aspect of the first reinforced passageway 200, theinsertion tab 23″ extends away from the common perimeter edge 11″ adistance of about one-sixteenth of an inch ( 1/16″). The inventorsherein experimented with shorter and longer insertion tabs (not shown),and determined that the one-sixteenth of an inch insertion tab 23″produced the greatest shatter resistance of the optically-transparentpanel 204 of the first reinforced passageway 200.

In another aspect of the first reinforced passageway 200, theshatter-resistant, optically-transparent transparent panel 204 isconfigured so that an entire perimeter edge of the polycarbonate sheet30″ defines the insertion tab 23″ so that the insertion tab 23″ of thepolycarbonate sheet 30″ extends beyond the entire common perimeter edge1″.

In a further aspect of the first reinforced passageway 200, the outsidewall 244 of the second stop 242 and the second structural surface 208form part of an interior side 256 of the reinforced passageway 200. By“interior side 256” it is meant that the reinforced passageway 200 ispart of an enclosed structure (not shown), such as a school building,having and “inside volume” enclosed by walls (not shown) , a roof (notshown) and passageways, etc. The “interior side 256” is a side 256 ofthe reinforced passageway 200 facing the inside volume (not shown) ofthe enclosed school building structure (not shown). Keeping the secondfastener 248 of the second stop 242 in the interior side 256 of theenclosed structure (not shown) prevents an unwanted intruder (not shown)from unfastening the second stop (242) to mechanically remove theshatter proof, optically-transparent panel 204.

An additional embodiment of the present disclosure includes a secondreinforced passageway that is shown in FIG. 8A in a fragmentary,cross-sectional view and is generally designated by the referencenumeral 300. An entire second reinforced passageway (not shown) may bein the form of a door or a window, similar to the passageway 70 shown inFIG. 3. The second reinforced passageway 300 substantially improvestwo-piece kits (an exemplary two-piece kit being described in detailbelow) known in the art to secure transparent panels to a frame 72 of apassageway 70. Exemplary two-piece panel mounting kits are availablefrom the CURRIES Company of Mason City, Iowa.

(See: www.curries.com/Other/Curries/Documents/-tech door9-10%202-9-09.pdf.)

The second reinforced passageway 300 includes a frame 302 surrounding atransparent panel 204. (For purposes of efficiency and avoidingredundant detail, the shatter-proof, optically-transparent panel 204secured within the second reinforced passageway 300 shown in FIGS. 8Aand 8B will be the same transparent panel 204 described above withrespect to the first reinforced passageway 200.) The frame 302 includesa first structural surface 304, an opposed second structural surface 306and a top structural surface 308 secured perpendicular to and extendingbetween a first top edge 310 of the first structural surface 304 and asecond top edge 312 of the second structural surface 306.

More particularly, the second reinforced passageway 300 includes, afirst piece 314 of a two-piece transparent panel mounting kit 316. Thefirst piece 314 has a first wall 318 secured adjacent the first top edge310 of the first structural surface 304. The first wall 318 extends apre-determined distance away from the first structural surface 304 andthe top structural surface 308. The first wall 318 also includes a firstcavity wall 320 extending back toward the top structural surface 308.The first wall 318 also includes a first grab-cleat 322 that extendsbelow the first top edge 310 of the first structural surface 304 and issecured adjacent the first structural surface 304. The second reinforcedpassageway 300 also includes a second piece 324 of the two-piecetransparent panel mounting kit 316. The second piece 324 has a secondwall 326 secured adjacent the second top edge 312 of the secondstructural surface 306 and the second wall 326 extends a pre-determineddistance away from the second structural surface 306 and the topstructural surface 308. The second wall 326 also includes a secondcavity wall 328 that extends toward the top structural surface. Thesecond wall also includes a second grab-cleat 330 that extends below thesecond top edge 312 of the second structural surface 306 and is securedadjacent the second structural surface 306.

As shown in FIG. 8A, the first cavity wall 320 and the second cavitywall 328 are configured to define a panel mounting cavity 332 betweenthe first and second cavity walls 320, 328. A bead of blast proofcaulking 334 is secured within the mounting cavity 332 between thecavity walls 320, 328 and adjacent a lower portion 336 of the firstcavity wall 320 and a lower portion 337 of the second cavity wall 328. Afirst layer of glazing tape 338 is secured along an upper portion 340 ofthe first cavity wall 320. A second layer of glazing tape 342 is securedalong an upper portion 344 of the second cavity wall 328.

The optically-transparent panel 240 is secured within the mountingcavity 332, within the bead of blast proof caulking 334 the mountingcavity 332, and between and adjacent first and second layers of glazingtape 338, 342 on the first and second cavity walls 320, 328. Theoptically-transparent panel 204 is a shatter-resistant five-layer thinpanel 10, 204 or a shatter-resistant seven-layer thick panel 60described above. The transparent panel 204 has a weight no greater thanabout 4.6 pounds per square foot. The polycarbonate sheet 30″ defines aninsertion tab 23″ extending beyond a common perimeter edge 11″ of thenon-polycarbonate sheets, as described above with respect to FIG. 7.

The optically-transparent panel 204 is secured within the mountingcavity 332 so that the insertion tab 23″ is closer to the top structuralsurface 308 than the common perimeter edge 11″. A kit-fastener 346passes through the first and second pieces 314, 324 of the two-piecetransparent panel mounting kit 316. The kit-fastener 346 and the twopieces 314, 324 of the kit 316 are configured so that the kit-fastener346 selectively draws the two pieces 314, 324 toward each other tothereby decrease a volume within the mounting cavity 332 to secure theoptically-transparent panel 204 within the mounting cavity 332 of thetwo-piece kit 316.

In another aspect of the second reinforced passageway 30, the insertiontab 23″ extends away from the common perimeter edge 11″ a distance ofabout one-sixteenth of an inch, as represented by reference numeral 348in FIG. 8B.

In an additional aspect of the second reinforced passageway 300, anentire perimeter edge 23″ of the polycarbonate sheet 30″ defines theinsertion tab 23″ so that the insertion tab 23″ of the polycarbonatesheet 30″ extends beyond the entire common perimeter edge 11″.

In a further aspect of the second reinforced passageway 300, thekit-fastener 346 comprises a metal screw having a driving head 350 and athreaded body 352 wherein the driving head 350 is secured adjacent oneof the first piece 314 and the second piece 324 of the two-piece kit316. The piece 314, 324 with the driving head 350 of the kit-fastener344 forms part of an interior side 354 of the second reinforcedpassageway 300. In FIG. 8A, the interior side 354 therefore wouldinclude the first piece 314 of the kit 316.

Testing by the inventors has established an enormous increase inshatter-resistance of the described panels 10, 60, 204 that providesdramatically enhanced security for persons (not shown) within aninterior of a building (not shown) protected by the reinforcedpassageways 200, 300, such as doors and windows that a retrofitted withthe thin 10 or thick 60 panels within the first or second reinforcedpassageways 200, 300 embodiments of the present disclosure. Priorefforts to obtain anywhere near the same level of intrusion resistancenecessarily included complete removal of the passageway frame andreplacement with a frame that can support bullet-proof or intrusionresistant glass weighing typically more than 25 pounds per square foot,which is a very costly and time-consuming undertaking. In contrast, thepanels 10, 60, 204 of the present first and second reinforcedpassageways 200, 300 weigh between about 4.1 pounds and 4.6 pounds persquare foot, and hence can be easily supported by a standard doorpassageway frame 72 configured to support one-quarter inch, standardtempered glass panels (not shown) commonly utilized in public schoolbuildings.

It is noted that all of the embodiments 10, 60 , 200, 300 of the presentdisclosure include an insertion tab 23, 61, 23″ extending beyond theperimeter edge 11, 11″ of the panels. The inventors have experimentedwith the panels with and without the insertion tab 23, 61, 23″. Theyhave determined that when the panels 10, 60, 204 are secured within thefirst and/or second reinforced passageway embodiments 200, 300, thepanels with the insertion tab 23, 61, 23″ perform dramatically betterthan the panels within the reinforced passageways 200, 300 with noinsertion tab 23, 61, 23″. As noted above, the inventors have alsoundertaken experiments to determine an optimal length of the insertiontab 23, 61, 23″, which is about one-sixteenth of an inch, as shown inFIG. 8B at reference numeral 348.

The inventors have proposed a reason that the insertion tab 23, 61, 23″produces such dramatically enhanced characteristics. First, the panels10, 60, 204 are secured in both the first and second reinforcedpassageway embodiments 200, 300 so that the panels 10, 60, 204 do notcontact any adjacent metal, and instead are only contacted by the beadblast-proof caulking 232, 334 and the strips of compressible glazingtape 236, 252, 338, 342. Therefore, whenever the panels 10, 60, 204receive an impact, a vibration is initiated. The insertion tab 23, 61,23″ facilitates limited movement of the tap 23, 61, 23″ within the beadof blast-proof caulking 232, 334 that effectively dampens and diffusesthe vibration to decrease the probability of any damage to the panels10, 60, 204 at the location of the panels being secured within thepassageway frame 70. This limited movement of the invention tab 23, 61,23″ is permitted while the panels 10, 60, 204 are firmly securedadjacent the top structural surface 210, 308 of the frame 202, 302 andprotected against contact with any metal stops 220, 242 or metal cavitywalls 320, 328 by the unique use of the strips of compressive glazingtape 236, 252, 338, 342 and the bead of blast-proof caulking 232, 334.

Production of the thin embodiment 10, 204 and the thick embodiment 60,involve assembly of the embodiments 10, 60 within heated vacuum chambers(not shown) under conditions that are known in the production of priorart multi-layered, intrusion resistant, optically-transparent panels(not shown).

For purposes herein, the word “about” is to mean plus or minustwenty-percent. Additionally, the word “thickness” is to mean a shortestdistance between opposed surfaces or the described object.

While the present disclosure has been presented above with respect tothe described and illustrated embodiments of the shatter-resistant,optically-transparent panels 10, 60, 204 and methods of use of thepanels for on-site retrofitting to produce reinforced passageways 200,300, it is to be understood that the disclosure is not to be limited tothose alternatives and described embodiments. Accordingly, referenceshould be made primarily to the following claims rather than theforgoing description to determine the scope of the disclosure.

What is claimed is:
 1. A reinforced passageway supporting ashatter-resistant, optically-transparent panel, the passageway includinga frame surrounding the transparent panel, the frame including a firststructural surface, an opposed second structural surface and a topstructural surface secured perpendicular to and extending between topedges of the first and second structural surfaces, the reinforcedpassageway comprising: a. an integral first stop and base plate thatincludes a box shaped first stop having a base plate as a base of thefirst stop and extending away from the first stop, the base plate beingsecured adjacent to and parallel with the top structural surface, anoutside wall of the first stop being secured to the base plate andadjacent the top edge of the first structural surface and extending awayfrom the first structural surface and top structural surface, an insidewall of the first stop secured to the base plate opposed to the outsidewall and extending away from the base plate and top structural surface,the base plate including a plate extension extending along the topstructural surface in a direction away from the outside and insidewalls, and a first fastener passing through the base plate extension tofasten the integral first stop and base plate to the top structuralsurface; b. a bead of blast proof caulking secured over the firstfastener between and along the base plate extension and a lower portionof the inside wall of the first stop; c. a first layer of glazing tapesecured to an upper portion of the inside wall extending from adjacentthe bead of blast proof caulking along the inside wall parallel to thebead and extending to cover the upper portion of the inside wall; d. asetting block secured within the bead of blast proof caulking andadjacent the base plate extension; e. the optically-transparent panelsecured within the bead of blast proof caulking upon the setting blockand adjacent the first layer of glazing tape, the optically-transparentpanel being one of a shatter-resistant five-layer thin panel and ashatter-resistant seven-layer thick panel, each of the panels includingopposed first and second glass sheets, first and second urethane sheetsbetween the first and second glass sheets, and a polycarbonate sheetbetween the urethane sheets, wherein the transparent panel has a weightno greater than about 4.6 pounds per square foot, and wherein thepolycarbonate sheet defines an insertion tab extending beyond a commonperimeter edge defined by the glass sheets and the urethane sheetsoverlying each other, the optically-transparent panel secured to theintegral first stop and base plate so that the insertion tab is adjacentthe setting block; f. a second stop including an outside wall of thesecond stop secured to the top structural surface and adjacent the topedge of the second structural surface and extending away from the secondstructural surface and top structural surface, an inside wall of thesecond stop secured to the top structural surface opposed to the outsidewall and extending away from the top structural surface, and a secondfastener passing through a top surface of the second stop between theinside and outside walls of the second stop and through the topstructural surface of the frame to secure the second stop to the topstructural surface of the frame; and, g. a second layer of glazing tapesecured to an upper portion of the inside wall of the second stop andextending adjacent the transparent panel and along the inside wall ofthe second stop to cover the upper portion of the inside walls of thesecond stop.
 2. The reinforced passageway of claim 1, wherein theinsertion tab extends away from the common perimeter edge a distance ofabout one-sixteenth of an inch.
 3. The shatter-resistant,optically-transparent panel of claim 1, wherein an entire perimeter edgeof the polycarbonate sheet defines the insertion tab so that theinsertion tab of the polycarbonate sheet extends beyond all of thecommon perimeter edge.
 4. The reinforced passageway of claim 1, whereinthe outside wall of the second stop and the second structural surfaceform part of an interior side of the reinforced passageway.
 5. Areinforced passageway supporting a shatter-resistant,optically-transparent panel, the passageway including a framesurrounding the transparent panel, the frame including a firststructural surface, an opposed second structural surface and a topstructural surface secured perpendicular to and extending between topedges of the first and second structural surfaces, the reinforcedpassageway comprising: a. a first piece of a two-piece transparent panelmounting kit, the first piece having a first wall secured adjacent thetop edge of the first structural surface and the first wall extending apre-determined distance away from the first structural surface and thetop structural surface, the first wall also including a first grab-cleatextending below the top edge of the first structural surface andadjacent the first structural surface; b. a second piece of thetwo-piece transparent panel mounting kit, the second piece having asecond wall secured adjacent the top edge of the second structuralsurface and the second wall extending a pre-determined distance awayfrom the second structural surface and the top structural surface andthe second wall also including a second cavity wall extending toward thetop structural surface, the second wall also including a secondgrab-cleat extending below the top edge of the second structural surfaceand adjacent the second structural surface; c. the first cavity wall andthe second cavity wall configured to define a panel mounting cavitybetween the walls; d. a bead of blast proof caulking secured within themounting cavity between the cavity walls and adjacent lower portions ofthe first and second cavity walls; e. a first layer of glazing tapesecured along an upper portion of the first cavity wall and a secondlayer of glazing tape secured along an upper portion of the secondcavity wall; and, f. the optically-transparent panel secured within themounting cavity and within the bead of blast proof caulking and betweenand adjacent the first and second layers of glazing tape on the firstand second cavity walls, the optically-transparent panel being one of ashatter-resistant five-layer thin panel and a shatter-resistantseven-layer thick panel, each of the panels including opposed first andsecond glass sheets, first and second urethane sheets between the firstand second glass sheets, and a polycarbonate sheet between the urethanesheets, wherein the transparent panel has a weight no greater than about4.6 pounds per square foot, and wherein the polycarbonate sheet definesan insertion tab extending beyond a common perimeter edge defined by theglass sheets and the urethane sheets overlying each other, theoptically-transparent panel secured within the mounting cavity so thatthe insertion tab is closer to the top structural surface than thecommon perimeter edge; and, g. a kit-fastener passing through the firstand second pieces of the two-piece transparent panel mounting kit andconfigured so that the kit-fastener selectively draws the two piecestoward each other to thereby decrease a volume within the mountingcavity to secure the optically-transparent panel within the mountingcavity of the two-piece kit.
 6. The reinforced passageway of claim 5,wherein the insertion tab extends away from the common perimeter edge adistance of about one-sixteenth of an inch.
 7. The shatter-resistant,optically-transparent panel of claim 5, wherein an entire perimeter edgeof the polycarbonate sheet defines the insertion tab so that theinsertion tab of the polycarbonate sheet extends beyond all of thecommon perimeter edge.
 8. The reinforced passageway of claim 5, whereinthe kit-fastener comprises a metal screw having a driving head andthreaded body wherein driving head is secured adjacent one of the firstand second pieces of the two-piece kit, and the piece with the drivinghead of the metal screw forms part of an interior side of the reinforcedpassageway.